In many cases, for instance when mounting door-frames and window-frames, it is desirable, even necessary, to be able to adjust the frame in relation to the wall which usually is not level and is often times vertical. Various methods for mounting door-frames exist, the most usual one using screws or nails as well as wedges. In this case, it is very difficult to adjust the door-frame afterwards. In order to simplify after-adjustment, different forms of sleeves with fixed or loose screws are used when mounting the door frame. Specially made adjusting screws are also employed.
Common to known mounting methods is that they require special measures in addition to preboring and counterboring for the mounting screw. In certain cases special screws are required.
A solution of the problem is discussed in Swedish Patent No. 8402786-1 showing a screw lock which is screwed home in the usual manner together with the screw after the required and stanardized preboring with countersinking. No special tools or special measures other than the application of the screw lock onto the screw are required. However, it has been found that this screw lock requires a large investment in machines for manufacture due to its relatively complicated form and due to the fact that it must be made of metal, and therefore the price per unit will be relatively large. Moreover, this screw lock can only be used in countersunk boreholes, especially in wood and particle board.